Over the past couple of years I've taken various classics courses that have briefly mentioned the Sea Peoples yet none actually went into any depth of who they actually were. Is this something that simply isn't known to us?
This is a pretty popular topic, so check out the Sea Peoples section of the r/askhistorians FAQ.
I wrote about the Philistines in Tell me about the Philistines vs others in the Levant 1200 to 800 BCE and some of the other groups in What do we know about the so-called Sea People's origins?